• 한국재료학회지
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• 제15권12호
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• pp.829-832
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• 2005

Thermal analysis of new designed heat-sink models was carried out according to the natural ana the forced convection using computational fluid dynamics(CFD). Heat resistance of wave type, top vented wave type and plate type of heat sink was compared with each other As the direction of fin and air flow are vertical(z-axis), it is shown that radiant heat performance of all of heat sinks was superior than other experimental conditions. Especially, the heat resistance of top vented wave heat sink was $0.17^{\circ}C/W$(forced convection) and $0.48^{\circ}C/W$(natural convection). The radiant heat performance of heat sink was increased with increasing the height of fin and the width of fin pitch.

• 한국전기전자재료학회논문지
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• 제25권2호
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• pp.100-104
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• 2012

Fin-type SONOS (silicon-oxide-nitride-oxide-silicon) flash memory has emerged as novel devices having superior controls over short channel effects(SCE) than the conventional SONOS flash memory devices. However despite these advantages, these also exhibit undesirable characteristics such as corner effect. Usually, the corner effect deteriorates the performance by increasing the leakage current. In this paper, the corner effect of fin-type SONOS flash memory devices is investigate by 3D Process and device simulation and their electrical characteristics are compared to conventional SONOS devices. The corner effect has been observed in fin-type SONOS device. The reason why the memory characteristic in fin-type SONOS flash memory device is not improved, might be due to existing undesirable effect such as corner effect as well as the mutual interference of electric field in the fin-type structure as reported previously.

• 한국어류학회지
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• 제13권2호
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• pp.117-122
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• 2001

강원도 삼척시 호산리 호산천에서 채집된 꾹저구, 검정꾹저구, 무늬꾹저구 3종의 성적이형에 관하여 조사하였다. 3종은 산란기때 뚜렷한 혼인색을 나타낸다. 3종 모두 암컷에서는 두부복면, 배지느러미, 제 1 등지느러미 외연이 진한 흑색을 나타냈다. 그러나 검정꾹저구의 제 1 등지느러미 외연으로부터 1/3은 진한 흑색을 나타낸 반면 다른 2종은 짙은 황색을 나타내는 차이를 보였다. 3종의 암컷모두 복부가 짙은 황색이 되는 공통점을 나타내었다. 수컷인 경우, 꾹저구와 무늬꾹저구는 거의 같은 혼인색을 나타냈으나 뒷지느러미에 있어서 무늬꾹저구는 짙은 흑색을 나타내었고, 꾹저구는 옅은 흑색을 나타내었다. 검정꾹저구는 두부복면, 배지느러미 및 뒷지느러미가 황색을 나타낸 반면, 나머지 2종은 옅은 흑색을 나타내었다. 이들 3종의 수컷 생식공돌기는 좁고 긴 삼각형 모양이었고, 암컷은 굵고 짧은 하트모양이었다. 꾹저구는 7개의 형질 즉, 체고, 두장, 문장, 상악장, 두고, 가슴지느러미 길이, 안경 등에서 암수간에 유의한 차이가 인정되었다. 검정꾹저구는 11개의 형질 즉, 체고, 미병장, 미병고, 두고, 두장, 문장, 상악장, 두폭, 뒷지느러미 길이, 가슴지느러미 길이 및 꼬리지느러미 길이 등에서 유의한 차이가 인정되었다. 무늬꾹저구는 10개의 형질 즉, 체고, 두장, 미병고, 문장, 상악장, 두폭, 뒷지느러미 길이, 가슴지느러미 길이, 꼬리지느러미 길이 및 안경 등에서 유의한 차이가 인정되었다. 이들 형질중, 체고, 두장, 문장, 상악장 및 가슴지느러미 길이 등은 3종 모두 암수간에 유의한 차이가 인정된 형질이었는데 암컷은 체고에서만 수컷보다 높은 수치를 나타냈고, 나머지 형질에서는 수컷이 암컷보다 높은 수치를 나타냈다. 또한 암수간에 가장 큰 차이로 쉽게 구분이 가능했던 형질은 상악장으로써 수컷의 상악장은 암컷의 후연을 훨씬 넘었다 (p<0.001).

• 한국수산과학회지
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• 제53권4호
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• pp.572-576
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• 2020

As grouper aquaculture production intensifies worldwide, hybrids are increasingly produced to induce heterosis of traits such as rapid growth and strong environmental adaptability. In this study, we compared the morphological characteristics of a hybrid grouper to those of its parent species Epinephelus moara and E. lanceolatus. The coefficients of external and skeletal traits evaluated using soft X-rays did not differ significantly among groups; however, several patterns were detected among measured traits. The body depth (BD), length of caudal peduncle (LCP), and pre-anal fin length (PAL) of the hybrid were the same as those of E. moara, whereas the pre-pectoral fin length (PPL) and interorbital width (IOW) of the hybrid were the same as those of E. lanceolatus. Traits that did not differ significantly among the three groups included pre-dorsal fin length (PDL), pre-ventral fin length (PVL), length of anal fin (LAF), and length of dorsal fin (LDF), whereas the depth of caudal peduncle (DCP) and snout length (SNL) showed intermediate traits, and eye diameter (ED) was significantly smaller in the hybrid. Therefore, intermediate traits such as DCP and SNL and specific traits such as ED may be used as indices for hybrid classification.

• 대한기계학회논문집B
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• 제25권1호
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• pp.117-123
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• 2001

In present study a methodology has been developed and applied for the optimum design and performance evaluation of microchannel heat sinks. The optimum design parameters include channel number and fin thickness. For a trial model of 127mm in length, 52.5mm in width, 16mm in height and 2.5mm in base thickness, the optimum channel number and the fin thinckness have been determined to be of 194 and 0.08359mm, respectively in laminar flow region. Performance of the optimally designed microchannel heat sinks has been compared with those having 50% and 150% of the number of channels. The results showed that the 50% and 150% designs increased the pumping power by 200% and 150%, respectively.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권2호
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• pp.76-81
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• 2007

Threshold voltage ($V_{th}$) modeling of doublegate (DG) MOSFETs was performed, for the first time, by considering barrier lowering in the short channel devices. As the gate length of DG MOSFETs scales down, the overlapped charge-sharing length ($x_h$) in the channel which is related to the barrier lowering becomes very important. A fitting parameter ${\delta}_w$ was introduced semi-empirically with the fin body width and body doping concentration for higher accuracy. The $V_{th}$ model predicted well the $V_{th}$ behavior with fin body thickness, body doping concentration, and gate length. Our compact model makes an accurate $V_{th}$ prediction of DG devices with the gate length up to 20-nm.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1149-1154
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• 2008

The present study investigates the heat transfer characteristics on concave surface with array impinging jet and fin arrangement. The heat transfer coefficients was measured by TLC method. The Reynolds number based on jet hole diameter is 10,000 and hole diameter-to-plate distance ratio (H/d) is fixed at 2. The rectangular fins are installed in the curved channel and the width of fin varies from 1d to 3d. Without fins, the averaged heat transfer coefficients decreases as moves downstream region. While, the rectangular fins block the crossflow and higher heat transfer rates were observed compared to smooth channel.

• 설비공학논문집
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• 제15권10호
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• pp.860-869
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• 2003

Design optimization of the heat sink with 7${\times}$7 square pin-fins is performed numerically using the Computational Fluid Dynamics (CFD) and the Computer Aided Optimization (CAO). In the pin-fins heat sink, the optimum design variables for fin height (h), fin width (w), and fan-to-heat sink distance (c) can be achieved when the thermal resistance ($\theta$$_{j}$) at the junction and the overall pressure drop ($\Delta$p) are minimized simultaneously. To complete the optimization, the finite volume method for calculating the objective functions, the BFGS method for solving the unconstrained non-linear optimization problem, and the weighting method for predicting the multi-objective problem are used. The results show that the optimum design variable for the weighting coefficient of 0.5 are as follows: w=4.653 mm, h=59.215 mm, and c=2.667 mm. In this case, the objective functions are predicted as 0.56K/W of thermal resistance and 6.91 Pa of pressure drop. The Pareto optimal solutions are also presented.re also presented.d.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1418-1423
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• 2004

Optimization of a heat exchanger with internally finned circular tubes has been performed for three-dimensional periodically fully developed turbulent flow and heat transfer. The design variables of fin number N, fin width ($d_1,d_2$) and fin height(H), are numerically optimized for the limiting conditions of $N=22{\sim}37$, $d_1=0.5{\sim}1.5$ mm, $d_2=0.5{\sim}1.5$ mm, $H=0.1{\sim}1.5$. Due to the periodic boundary conditions along main flow direction, the three layers of meshes are considered. The CFD and the mathematical optimization are coupled to optimize the heat exchanger. The flow and thermal fields are predicted using the finite volume method and the optimization is carried out by using the sequential quadratic programming (SQP) method which is widely used in the constrained nonlinear optimization problem.

• 환경생물
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• 제18권4호
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• pp.387-394
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• 2000

1990년 6월부터 1999년 9월까지 채집된 한국산 꾹저구, 무늬꾹저구, 검정꾹저구 3종의 성별에 따른 형태적 특징을 비교 분석하였다. 한국산 꾹저구속 3종은 암컷과 수컷 모두 측정한 13개의 형질 중 꼬리지느러미 길이를 제외한 12개의 형질에서 종간에 유의적 차이가 인정되었고, 이들 3종간에 각 차이의 유무를 알아보기 위한 다중비교분석 결과, 암컷의 경우 3종 모두 종간 구별이 되는 형질은 6개의 형질 즉, 체고, 두장, 미병장, 미병고, 문장, 가슴지느러미 길이였다. 무의꾹저구는 상악장, 뒷지느러미 길이, 안경이 다른 2종보다 짧았으며 두폭, 두고는 3종 중 가장 작았고, 꾹저구는 배지느러미 길이가 가장 길었다. 한편 수컷의 경우 3종 모두 종간 구별이 되는 형질은 없었으나, 꾹저구의 수컷은 두장, 안경, 배지느러미 길이가 가장 길었으며, 무의꾹저구는 미병장이 가장 길었고, 문장과 뒷지느러미 길이가 가장 짧았으며 두고는 가장 낮았다. 검정꾹저구의 수컷은 체고와 미병고가 월등히 높아서 다른 2종과 뚜렷히 구별되었으며, 상악장과 가슴지느러미 길이도 3종 중 가장 길었다.